Conventional internal combustion engines operate using liquid fuels such as gasoline or diesel fuel. The liquid fuel is pumped by a fuel pump to the engine and delivered under low pressure to a carburetor or under high pressure to a fuel injection system.
A carburetor uses engine vacuum or suction created by intake air accelerated through a venturi tube to draw liquid fuel into an airstream in an intake manifold. Fuel injection systems have more recently replaced carburetors in many engine applications. A fuel injection system atomizes liquid fuel by forcibly pumping it through a small nozzle under high pressure into an intake manifold or directly into a combustion chamber.
Unfortunately, carburetors and fuel injection systems have numerous manufacturing and operational drawbacks. Carburetors and fuel injection systems both have components with small passages and tight tolerances that are expensive to fabricate. The small passages are subject to clogging by debris and accumulated varnish and gum from the fuel over time. The clogged passages are difficult to identify, locate and effectively clean. Another problem with carburetors and fuel injection systems is that they do not completely atomize the liquid fuel which causes increased fuel consumption, increased exhaust emissions and pollution. A reduction in exhaust emissions can reduce the need for expensive pollution control components.